Astm c 759 10

Designation C759 − 10 Standard Test Methods for Chemical, Mass Spectrometric, Spectrochemical, Nuclear, and Radiochemical Analysis of Nuclear Grade Plutonium Nitrate Solutions1 This standard is issued[.]

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Designation: C759−10

Standard Test Methods for

Chemical, Mass Spectrometric, Spectrochemical, Nuclear,

and Radiochemical Analysis of Nuclear-Grade Plutonium

Nitrate Solutions1

This standard is issued under the fixed designation C759; the number immediately following the designation indicates the year of

original adoption or, in the case of revision, the year of last revision A number in parentheses indicates the year of last reapproval A

superscript epsilon (´) indicates an editorial change since the last revision or reapproval.

1 Scope

1.1 These test methods cover procedures for the chemical,

mass spectrometric, spectrochemical, nuclear, and

radiochemi-cal analysis of nuclear-grade plutonium nitrate solutions to

determine compliance with specifications

1.2 The analytical procedures appear in the following order:

Sections

Plutonium by Amperometric Titration with Iron(II) 2

Plutonium by Diode Array Spectrophotometry

Free Acid by Titration in an Oxalate Solution 8 to 15

Free Acid by Iodate Precipitation-Potentiometric Titration

Test Method

16 to 22 Uranium by Arsenazo I Spectrophotometric Test Method 23 to 33

Thorium by Thorin Spectrophotometric Test Method 34 to 42

Iron by 1,10-Phenanthroline Spectrophotometric Test Method 43 to 50

Impurities by ICP-AES

Chloride by Thiocyanate Spectrophotometric Test Method 51 to 58

Fluoride by Distillation-Spectrophotometric Test Method 59 to 66

Sulfate by Barium Sulfate Turbidimetric Test Method 67 to 74

Plutonium —238 Isotopic Abundance by Alpha Spectrometry

Americium-241 by Extraction and Gamma Counting 77 to 85

Gamma-Emitting Fission Products, Uranium, and Thorium by

Gamma-Ray Spectroscopy

94 to 102 Rare Earths by Copper Spark Spectrochemical Test Method 103 to 105

Tungsten, Niobium (Columbium), and Tantalum by Spectro

chemical Test Method

106 to 114 Sample Preparation for Spectrographic Analysis for General

Impurities

115 to 118 1.3 The values stated in SI units are to be regarded as

standard The values given in parentheses are for information

only

1.4 This standard does not purport to address all of the

safety concerns, if any, associated with its use It is the

responsibility of the user of this standard to establish

appro-priate safety and health practices and determine the

applica-bility of regulatory limitations prior to use For specific

safeguard and safety hazard statements, see Section 6

2 Referenced Documents

2.1 ASTM Standards:3 C697Test Methods for Chemical, Mass Spectrometric, and Spectrochemical Analysis of Nuclear-Grade Plutonium Dioxide Powders and Pellets

C852Guide for Design Criteria for Plutonium Gloveboxes

C1009Guide for Establishing and Maintaining a Quality Assurance Program for Analytical Laboratories Within the Nuclear Industry

C1068Guide for Qualification of Measurement Methods by

a Laboratory Within the Nuclear Industry

C1108Test Method for Plutonium by Controlled-Potential Coulometry

C1128Guide for Preparation of Working Reference Materi-als for Use in Analysis of Nuclear Fuel Cycle MateriMateri-als

C1156Guide for Establishing Calibration for a Measure-ment Method Used to Analyze Nuclear Fuel Cycle Mate-rials

Controlled-Potential Coulometry in H2SO4at a Platinum Working Electrode

C1206Test Method for Plutonium by Iron (II)/Chromium (VI) Amperometric Titration(Withdrawn 2015)4

C1210Guide for Establishing a Measurement System Qual-ity Control Program for Analytical Chemistry Laborato-ries Within the Nuclear Industry

C1235Test Method for Plutonium by Titanium(III)/ Cerium(IV) Titration(Withdrawn 2005)4

C1268Test Method for Quantitative Determination of

241

Am in Plutonium by Gamma-Ray Spectrometry

C1297Guide for Qualification of Laboratory Analysts for the Analysis of Nuclear Fuel Cycle Materials

1 These test methods are under the jurisdiction of ASTM Committee C26 on

Nuclear Fuel Cycle and are the direct responsibility of Subcommittee C26.05 on

Methods of Test.

Current edition approved June 1, 2010 Published July 2010 Originally approved

in 1973 Last previous edition approved in 2004 as C759 – 04 DOI: 10.1520/

C0759-10.

2 Discontinued as of November 15, 1992.

3 For referenced ASTM standards, visit the ASTM website, www.astm.org, or

contact ASTM Customer Service at service@astm.org For Annual Book of ASTM Standardsvolume information, refer to the standard’s Document Summary page on

the ASTM website

4 The last approved version of this historical standard is referenced on www.astm.org.

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C1307Test Method for Plutonium Assay by Plutonium (III)

Diode Array Spectrophotometry

C1415Test Method for238Pu Isotopic Abundance By Alpha

Spectrometry

C1432Test Method for Determination of Impurities in

Plutonium: Acid Dissolution, Ion Exchange Matrix

Separation, and Inductively Coupled Plasma-Atomic

Emission Spectroscopic (ICP/AES) Analysis

D1193Specification for Reagent Water

E50Practices for Apparatus, Reagents, and Safety

Consid-erations for Chemical Analysis of Metals, Ores, and

Related Materials

E115Practice for Photographic Processing in Optical

Emis-sion Spectrographic Analysis(Withdrawn 2002)4

E116Practice for Photographic Photometry in

Spectro-chemical Analysis(Withdrawn 2002)4

3 Significance and Use

3.1 These test methods are designed to show whether a

given material meets the purchaser’s specifications

3.1.1 An assay is performed to determine whether the

material has the specified plutonium content

3.1.2 Determination of the isotopic content of the plutonium

in the plutonium-nitrate solution is made to establish whether

the effective fissile content is in compliance with the

purchas-er’s specifications

3.1.3 Impurity content is determined by a variety of

meth-ods to ensure that the maximum concentration limit of

speci-fied impurities is not exceeded Determination of impurities is

also required for calculation of the equivalent boron content

(EBC)

4 Committee C26 Safeguards Statement 5

4.1 The material (plutonium nitrate) to which these test

methods apply is subject to nuclear safeguards regulations

governing its possession and use The following analytical

procedures in these test methods have been designated as

technically acceptable for generating safeguards accountability

measurement data: Plutonium by Controlled-Potential

Cou-lometry; Plutonium by Amperometric Titration with Iron(II);

Plutonium by Diode Array Spectrophotometry and Isotopic

Composition by Mass Spectrometry

4.2 When used in conjunction with appropriate Certified

Reference Materials (CRMs), these procedures can

demon-strate traceability to the national measurement base However,

adherence to these procedures does not automatically

guaran-tee regulatory acceptance of the resulting safeguards

measure-ments It remains the sole responsibility of the user of these test

methods to assure that their application to safeguards has the

approval of the proper regulatory authorities

5 Reagents and Materials

5.1 Purity of Reagents—Reagent grade chemicals shall be

used in all test methods Unless otherwise indicated, it is

intended that all reagents shall conform to the specifications of

the Committee on Analytical Reagents of the American Chemi-cal Society, where such specifications are available.6 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination

5.2 Purity of Water—Unless otherwise indicated, reference

to water shall be understood to mean reagent water conforming

to SpecificationD1193

6 Safety Hazards

6.1 Since plutonium bearing materials are radioactive and toxic, adequate laboratory facilities, gloved boxes, fume hoods, etc., along with safe techniques, must be used in handling samples containing these materials A detailed discussion of all the precautions necessary is beyond the scope of these test methods; however, personnel who handle these materials should be familiar with such safe handling practices as are given in Guide C852and in Refs ( 1 ) through ( 2 ).7

6.2 Adequate laboratory facilities, such as fume hoods and controlled ventilation, along with safe techniques, must be used

in this procedure Extreme care should be exercised in using hydrofluoric and other hot, concentrated acids Use of proper gloves is recommended Refer to the laboratory’s chemical hygiene plan and other applicable guidance for handling chemical and radioactive materials and for the management of radioactive, mixed, and hazardous waste

6.3 Hydrofluoric acid is a highly corrosive acid that can severely burn skin, eyes, and mucous membranes Hydroflu-oric acid is similar to other acids in that the initial extent of a burn depends on the concentration, the temperature, and the duration of contact with the acid Hydrofluoric acid differs from other acids because the fluoride ion readily penetrates the skin, causing destruction of deep tissue layers Unlike other acids that are rapidly neutralized, hydrofluoric acid reactions with tissue may continue for days if left untreated Due to the serious consequence of hydrofluoric acid burns, prevention of exposure or injury of personnel is the primary goal Utilization

of appropriate laboratory controls (hoods) and wearing ad-equate personal protective equipment to protect from skin and eye contact is essential

7 Sampling

7.1 A sample representative of the lot shall be taken from each lot into a container or multiple containers that are of such composition that corrosion, chemical change, radiolytic de-composition products, and method of loading or sealing will not disturb the chemical or physical properties of the sample (A flame-sealed quartz vial that is suitable for accommodating pressure resulting from radiolytic decomposition is generally considered to be an acceptable sample container.)

5 Based upon Committee C26 Safeguards Matrix ( C1009 , C1068 , C1128 , C1156 ,

C1210 , C1297 ).

6Reagent Chemicals, American Chemical Society Specifications, American

Chemical Society, Washington, DC For suggestions on the testing of reagents not

listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S Pharmacopeial Convention, Inc (USPC), Rockville,

MD.

7 The boldface numbers in parentheses refer to the list of references at the end of these test methods.

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7.2 Sample size shall be sufficient to perform the following:

7.2.1 Assay and acceptance tests at the seller’s plant,

7.2.2 Assay and acceptance tests at the purchaser’s plant,

and

7.2.3 Referee tests in the event they become necessary

7.3 All samples shall be identified clearly, including the

seller’s lot number

7.3.1 A lot is defined as any quantity of aqueous plutonium

nitrate solution that is uniform in isotopic, chemical, and

physical characteristics by virtue of having been mixed in such

a manner as to be thoroughly homogeneous

7.3.2 All containers used for a lot shall be identified

positively as containing material from a particular

homoge-neous solution

PLUTONIUM BY CONTROLLED-POTENTIAL

COULOMETRY

(This test method was discontinued in 1992 and replaced by

Test Method C1165.)

PLUTONIUM BY CONTROLLED-POTENTIAL

COULOMETRY

(With appropriate sample preparation, controlled-potential

coulometric measurement as described in Test Method

C1108 may be used for plutonium determination.)

PLUTONIUM BY AMPEROMETRIC TITRATION

WITH IRON(II)

(This test method was discontinued in 1992 and replaced by

Test MethodC1206.)

TEST METHOD FOR PLUTONIUM ASSAY BY

PLUTONIUM(III) DIODE ARRAY

SPECTROPHOTOMETRY

(With appropriate sample preparation, the measurement

de-scribed in Test MethodC1307may be used for plutonium

determination.)

FREE ACID BY TITRATION IN AN OXALATE

SOLUTION

8 Scope

8.1 This test method covers the determination of free acid in

plutonium nitrate solutions ( 3 , 4 ).

9 Summary of Test Method

9.1 Free acid is determined by titrating an aliquot of sample,

which contains an excess of ammonium oxalate added to

complex the plutonium, back to the original pH of the

ammonium oxalate solution with standard sodium hydroxide

solution Micropipets and microburets are required to measure

the small volume of sample and titrant used

10 Interferences

10.1 Any metal ions not complexed by oxalate which form

precipitates at the pH of the end point of the titration will cause

interference in this test method

N OTE 1—A “rule of thumb” is that 1 mL of saturated ammonium

oxalate solution will complex 6.4 mg of plutonium.

11 Apparatus

11.1 Magnetic Stirrer.

11.2 Microburet.

11.3 Micropipets.

11.4 pH Meter.

12.1 Ammonium Oxalate Solution, saturated.

12.2 Nitric Acid (3.50 N)—Prepare solution by diluting

concentrated nitric acid (HNO3, sp gr 1.42) with water

Standardize by titrating 0.500-mL aliquots with 0.100 N NaOH

solution

12.3 Sodium Hydroxide Solution (0.100 N)—Prepare and

standardize in accordance with PracticesE50

13 Procedure

13.1 Transfer 1.0 mL of saturated ammonium oxalate solu-tion to a small vial and dilute to about 2 mL with water 13.2 Add a stirring bar and insert the electrodes and start stirrer When the pH value becomes stable, record the value as the pH of reagent

N OTE 2—Normally, the pH value for the saturated solution is approxi-mately 6.4.

13.3 Add 20 µL of sample to the vial, rinse the pipet thoroughly with water, and stir the solution for 1 min

13.4 Titrate with 0.100 N NaOH solution to within one pH

unit of the end point; then, by adding successively smaller increments, titrate to the pH of the ammonium oxalate reagent and record the volume of titrant

N OTE 3—Allow time for the pH reading to stabilize between additions

of titrant as the end point is approached.

13.5 Make a daily check of the system by adding 20 µL of

3.50 N HNO3to a sample that has already been titrated to the

end point and titrate with standard 0.100 N NaOH solution

back to the same pH

14 Calculation

14.1 Calculate the free acid (H+, N) as follows:

H 1, N 5~A 3 N!/V (1)

where:

A = microlitres of standard NaOH solution required to titrate sample,

N = normality of NaOH standard solution, and

V = volume of sample, µL

15 Precision and Bias

15.1 Precision—Of individual results, 65 % at the 95 %

confidence level

15.2 Bias—99.4 %.

FREE ACID BY IODATE PRECIPITATION-POTENTIOMETRIC TITRATION TEST METHOD

16 Scope

16.1 This test method covers the determination of free acid

in strong acid solutions of plutonium nitrate

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17.1 Free acid is determined by potentiometric titration with

standard sodium hydroxide solution after precipitation and

subsequent removal of plutonium (up to 50 mg) as plutonium

iodate

18.1 Any hydrolyzable ions that are not precipitated with

iodate will interfere

19.1 Hydrochloric Acid (sp gr 1.19)—Concentrated

hydro-chloric acid (HCl)

19.2 Nitric Acid (1 + 14)—Dilute 14 volumes of water with

1 volume of concentrated nitric acid (HNO3, sp gr 1.42)

19.3 Potassium Iodate (0.3 M)—Dissolve 64.2 g of

potas-sium iodate (KIO3) in 900 mL of water, adjust the pH to 4.3 by

adding HNO3(1 + 14), and dilute to 1 L with water

19.4 Sodium Hydroxide (0.3 M)—Prepare and standardize in

accordance with Practices E50 after making the following

alterations: Use 15 mL of the NaOH solution (50 g/50 mL), and

in step 42.2, transfer 1.200 g of National Institute for Standards

and Technology (NIST) potassium acid phthalate SRM 84 h or

its replacement to a 250-mL Erlenmeyer flask instead of 0.4000

g

20 Procedure

20.1 Pipet 50 mL of KIO3(0.3 M) into a beaker and stir

while adding an aliquot of sample solution containing no

greater than 50 mg of plutonium

20.2 After precipitation is complete, filter the solution

through either a medium porosity glass frit or a fine textured

acid-washed filter paper and collect the filtrate in a beaker

20.3 Wash the precipitate with two 25-mL portions of 0.3 M

KIO3solution, and combine the washings with the filtrate from

step20.2

20.4 Dissolve the precipitate in HNO3(sp gr 1.42) or HCl

(sp gr 1.19) and transfer to a residue bottle

20.5 Transfer the sample from 20.3 to the titration

apparatus, position the electrodes and a magnetic stirring bar in

the solution, and start the stirrer

20.6 Titrate the free acid in the solution by adding the 0.3 M

NaOH solution from a 5-mL buret and plot the titration curve

(pH versus mL NaOH solution).

20.7 Determine the end point of the titration from the

midpoint of the inflection on the titration curve and record the

volume of 0.3 M NaOH solutions by the steps given in 20.5

through20.7of the procedure

21 Calculation

21.1 Calculate the free acid (H+, N) as follows:

H 1, N 5~Vs2 Vb!N/S (2)

where:

N = normality of NaOH solution,

Vs = millilitres of NaOH solution to titrate sample aliquot,

Vb = millilitres of NaOH solution to titrate reagent blank, and

S = millilitres of sample aliquot

22.1 The relative standard deviation, based on 49 titrations,

is 0.9 % for aliquots of sample containing a minimum of 0.2 milliequivalents of acid

22.2 Between 99 and 100 % of the free acid in standard plutonium (IV) solutions has been measured by this procedure; however, when the plutonium was in the (III) oxidation state,

the results showed a negative bias of as much as 8 % ( 5 ).

URANIUM BY ARSENAZO I SPECTROPHOTOMETRIC TEST METHOD

23 Scope

23.1 This test method covers the determination of uranium

in the range from 300 to 3000 µg/g of plutonium in plutonium nitrate solutions

24.1 Plutonium is reduced to Pu(III) in HCl (1 + 1) solution with hydroxylamine hydrochloride The uranium and pluto-nium are then separated by anion exchange, and the urapluto-nium is determined by measuring the absorbance of the U(VI)-Arsenazo I complex in a 1-cm cell at a wavelength of 600 nm

versus a reagent blank.

25 Interference

25.1 Iron at 500 µg/g of plutonium is the most likely interference in this test method

26 Apparatus

26.1 Columns, ion exchange, 1 by 10 cm Columns can be

made by sealing a 1-cm diameter filtering tube with a coarse glass frit to the bottom of a 40-mL centrifuge tube and cutting the tube off diagonally just below the frit

26.2 Spectrophotometer and 1-cm Matched Cells.

27.1 Ammonium Hydroxide (1 + 13)—Dilute 1 volume of

concentrated ammonium hydroxide (NH4OH, sp gr 0.90) with

13 volumes of water

27.2 Arsenazo I Reagent (0.500 g/L)—Dissolve 250 mg of

the purified reagent [(3-2-arsonophenylazo)-4,5-dihydroxy-2,7 naphthalenedisulfonic acid, disodium salt] in water and dilute

to 500 mL with water

N OTE 4—Purify reagents as follows: To a saturated aqueous solution of Arsenazo I, add an equal volume of HCl (sp gr 1.19), filter the orange precipitate, wash with acetonitrile, and dry at 100°C for 1 h.

27.3 Hydrochloric Acid (0.1 N)—To prepare, dilute 8.3 mL

of hydrochloric acid (HCl, sp gr 1.19) to 1 L with water

27.4 Hydrochloric Acid (1 + 1)—To prepare, dilute 500 mL

of hydrochloric acid (HCl, sp gr 1.19) to 1 L with water

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27.5 Hydroxylamine Hydrochloride Solution (100 g/L)—

Dissolve 10 g of (NH2OH·HCl) in water and dilute to 100 mL

with water

27.6 Nitric Acid (1 + 2)—Dilute 100 mL of nitric acid

(HNO3, sp gr 1.42) to 300 mL with water

27.7 Phenolphthalein Solution (0.25 g/L)—Dissolve 25 mg

of phenolphthalein in a water-ethanol (1 + 1) solution and

dilute to 100 mL with the water-ethanol solution

27.8 Plutonium Matrix Calibration Solution (7 g/L)—

Dissolve approximately 700 mg of plutonium metal, NIST

SRM 949e or its replacement, or other metal containing less

than 20 ppm of uranium in 5 mL of HCl (1 + 1), and dilute to

100 mL with HCl (1 + 1)

27.9 Sodium Cyanide Solution (50 g/L)—Dissolve 5 g of

sodium cyanide (NaCN) in water and dilute to 100 mL with

water

27.10 Resin, Anion Exchange—Use Dowex 1-X2 anion

exchange resin, chloride form, 100 to 200 mesh, or equivalent

resin

27.11 Stannous Chloride Solution (700 g/L)—Dissolve 7 g

of stannous chloride (SnCl2·2 H2O) in hydrochloric acid (HCl,

sp gr 1.19) and dilute to 10 mL with HCl (sp gr 1.19) Prepare

reagent fresh daily

27.12 Sulfuric Acid (1 + 2)—Dilute 1 volume of sulfuric

acid (H2SO4, sp gr 1.84) with 2 volumes of water

27.13 Sulfuric Acid (1 + 8)—Dilute 1 volume of sulfuric

acid (H2SO4, sp gr 1.84) with 8 volumes of water

27.14 Triethanolamine Buffer-Ethylenediamine-Tetraacetic

Acid Complexing Solution—Dissolve 74.5 g of triethanolamine

and 72 mg of ethylenediamine-tetraacetic acid, disodium salt

(EDTA) in 750 mL of water and 14.0 mL of nitric acid (HNO3,

sp gr 1.42) and dilute to 1 L with water Allow solution to stand

overnight before using

27.15 Uranium Standard Solution (20 mg/L)—Dissolve

23.60 mg of U3O8 (NIST SRM 950b or its replacement), or

uranium oxide of equal purity, in 1 mL of HNO3(1 + 2) and

dilute to 1 L with H2SO4(1 + 8)

28 Preparation of Ion Exchange Columns

28.1 Wash 250 g of the anion exchange resin alternately

with three 350-mL portions of HCl (sp gr 1.19) and three

350-mL portions of water Allow the resin to remain in each

solution for 30 min

28.2 Fill each column to a height of 10 cm with ion

exchange resin and rinse each column with 30 mL of HCl (sp

gr 1.19)

N OTE 5—Immediately before each analysis, rinse each column with 30

mL of HCl (sp gr 1.19) and remove any entrapped air from the column.

29 Calibration and Standardization

29.1 Pipet ten 10-mL aliquots of plutonium matrix

calibra-tion solucalibra-tion (7 g/L) into separate 50-mL beakers and add 2 mL

of H2SO4(1 + 2)

29.2 Add 0.0, 1.0, 4.0, 7.0, and 10.0 mL of uranium standard solution (20 mg/L), respectively, to each of the 5 pairs

of solutions prepared in 29.1and evaporate to dryness 29.3 Add 4.0 mL of HCl (1 + 1) to each beaker and dissolve the residue

29.4 Add 3 mL of hydroxylamine hydrochloride solution (NH2OH·HCl, 100 g/L) to each beaker and warm the solution under infrared lamps until the plutonium is reduced to Pu(III)

as indicated by the blue color If the solution is not blue, add more NH2OH·HCl solution and warm again

N OTE 6—Plutonium is not adsorbed on the resin if it is in the reduced Pu(III) state.

29.5 Cool the solutions to room temperature and add 3 drops of SnCl2·2 H2O solution (700 g/L) to each beaker

N OTE 7—The stannous chloride prevents air oxidation of the Pu(III) during subsequent steps in the procedure.

29.6 Add 13 mL of HCl (sp gr 1.19) to each beaker 29.7 Transfer each solution to a separate ion exchange column using five 1-mL portions of HCl (sp gr 1.19) to wash each beaker

29.8 Wash the Pu(III) from each column with six 5-mL portions of HCl (sp gr 1.19)

29.9 Next, elute the uranium from each column by washing

each column with six 5-mL portions of 0.1 N HCl Collect the

wash solutions from each column in a 50-mL beaker and evaporate to dryness on a hot plate under infrared lamps 29.10 Add 3 drops of HCl (sp gr 1.19) to dissolve each residue and wash the sides of the beaker with water

29.11 Add 4 drops of NaCN solutions (50 g/L) and 2 drops

of phenolphthalein solution to each beaker; then add NH4OH (1 + 13) until the indicator remains slightly pink

29.12 Pipet 5 mL of triethanolamine buffer and 3.0 mL of Arsenazo I solution to each beaker

29.13 Transfer each solution to a 25-mL volumetric flask and dilute to volume with water

29.14 Allow the solutions to stand 1 h for maximum color development, and then measure the absorbance at 600 nm in

1-cm cells versus a reference solution prepared from the

reagents starting at29.11

29.15 Calibration Curve:

29.15.1 Process the results obtained in29.14in accordance with the procedure described in31.1and31.2

29.15.2 Each time samples are analyzed verify the calibra-tion by processing duplicate aliquots of plutonium matrix calibration solutions containing no uranium; also process a set

of duplicates that contain 5 mL each of uranium standard (20 mg/L) added to aliquots of plutonium matrix calibration solution by the procedure given in 29.3through29.14 29.15.3 Process the results obtained in 29.15.2 in accor-dance with the procedure outlined in 31.3 If the individual calibration value disagrees at the 0.05 significance level with

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the value of the constant obtained from the complete

calibra-tion set, investigate and rectify the cause before proceeding

with further analyses

30 Procedure

30.1 Prepare duplicate reagent blanks starting with30.3

30.2 Transfer a sample aliquot containing approximately 70

mg of plutonium weighed to 60.1 mg into a 50-mL beaker

30.3 Add 5 mL of HCl (sp gr 1.19) to the beaker

30.4 Evaporate the solution to near dryness slowly to avoid

loss of sample

N OTE 8—This eliminates excess nitrate which would prevent reduction

of the plutonium.

30.5 Proceed with the analysis as described in29.3through

29.14

30.6 Calculate the concentration of uranium in micrograms

per gram of plutonium in accordance with instructions in

Section32

31 Calculation of Calibration Factors

31.1 Calculate the corrected absorbance value for each

standard solution as follows:

where:

Y = corrected absorbance value for standard,

r = absorbance value of standard obtained in29.14, and

s = average absorbance value obtained in 29.14 for the

duplicate calibration blanks with no uranium added

31.2 Use the least squares formulas and the data from31.1

to calculate values of A and B in the linear calibration equation:

where:

A, B = constants (B should be approximately zero),

Y = corrected absorbance value from31.1, and

x = micrograms of uranium in the standard calibration

solution

31.3 Calculate the individual calibration value for each

standard solution processed simultaneously with each set of

samples as follows:

where:

A' = individual calibration value for each standard solution,

n = micrograms of uranium in the standard solution, and

m = corrected absorbance of standard = p − q

where

p = absorbance for standard solution, and

q = average absorbance obtained from duplicate blank

solutions

31.4 Each individual value of A' should agree at the 0.05

significance level with the value of A obtained from the

complete calibration set

32 Calibration of Uranium Concentration

32.1 Calculate the uranium concentration in the sample, R,

micrograms per gram Pu, as follows:

where:

R = micrograms U per gram plutonium,

A, B = constants in linear calibration equation,

C = grams Pu per gram plutonium nitrate solution in

sample,

W = weight of sample aliquot, g, and

Y = a − b = corrected absorbance of sample solution where:

a = absorbance of sample solution, and

b = average absorbance of duplicate calibration blanks

33.1 In the range from 300 to 1100 µg U/g Pu the standard deviation is 6100 µg/g; in the range from 1500 to 3000 µg U/g

Pu it is 650 µg/g

THORIUM BY THORIN SPECTROPHOTOMETRIC

TEST METHOD

34 Scope

34.1 This test method covers the determination of 10 to 150

µg of thorium per gram of plutonium in plutonium nitrate solutions

35.1 Lanthanum is added as a carrier and is precipitated along with thorium as insoluble fluoride, while the plutonium remains in solution and is decanted after centrifugation of the sample The thorium and lanthanum fluoride precipitate is dissolved in perchloric acid, and the absorbance of the thorium-thorin complex is measured at a wavelength of 545 nm

versus a reference solution The molar absorptivity of the

colored complex is 15 600 for thorium concentration in the range from 5 to 70 µg Th/10 mL of the solution

36.1 Cations that form insoluble fluorides and colored complexes with thorin interfere in this test method

37 Apparatus

37.1 Infrared Heat Lamps, 250-W, borosilicate glass 37.2 Aluminum Heating Block—Drill a 150-mm high

alu-minum block to hold 16 12-mL centrifuge tubes and a thermometer In use the block is heated to 220°C

37.3 Platinum Stirring Rod, 1 mm in diameter by 160 mm

long

37.4 Spectrophotometer, with matched cells having 10-mm

light path

37.5 Vacuum Transfer Device, approximately 150 mm long

with a10⁄18standard-taper ground-glass joint that fits a 10-mL volumetric flask

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38.1 Ammonium Peroxydisulfate ((NH4)2S2O8)

38.2 Hydrochloric Acid (sp gr 1.19)—Concentrated

hydro-chloric acid (HCl)

38.3 Hydrofluoric Acid (1 + 24)—Dilute 1 volume of

con-centrated hydrofluoric acid (HF, sp gr 1.15) with 24 volumes of

water and store in a polyethylene wash bottle

38.4 Hydrogen Peroxide (30 %)—Concentrated hydrogen

peroxide (H2O2)

Dissolve 25 g of hydroxylamine hydrochloride (NH2OH·HCl)

in water and dilute to 100 mL with water

38.6 Lanthanum Nitrate Solution (10 g La/L)—Dissolve

3.12 g of lanthanum nitrate (La(NO3)3·6 H2O) in water and

dilute to 100 mL with water

38.7 Nitric Acid (sp gr 1.42)—Concentrated nitric acid

(HNO3)

38.8 Perchloric Acid (70 to 72 %)—Concentrated perchloric

acid (HClO4)

38.9 Silver Nitrate Solution (2.5 g/L)—Dissolve 250 mg of

silver nitrate (AgNO3) in water and dilute to 100 mL with

water Store solution in an amber bottle

38.10 Sulfuric Acid (1 + 35)—Add 1 volume of

concen-trated sulfuric acid (H2SO4, sp gr 1.84) to 35 volumes of water

38.11 Thorin Solution (1 g/L)—Dissolve 1 g of thorin

o-(2-hydroxy-3,6-disulfo-1-naphthylazo) benzenearsonic acid

disodium salt in water and dilute to 1 L

38.12 Thorium Standard Solution (20.00 mg/L)—Dissolve

20.00 mg of high-purity thorium as the metal, oxide, or nitrate

in HCl (sp gr 1.19) and H2O2(30 %) Add 83 mL of HClO4(70

to 72 %) and dilute to 1 L with water

39 Calibration and Standardization

39.1 Reference Standards and Blanks:

39.1.1 Pipet 1.00 mL of thorium standard (20 mg/L) into

each of two 20-mL beakers, 2.00 mL into each of 2 more

beakers and 3.00 mL into each of a third pair of beakers

39.1.2 To two additional 20-mL beakers and to each of the

solutions from 39.1.1, add 1 mL of HNO3(sp gr 1.42) and 2

mL of HClO4(70 to 72 %)

39.1.3 Evaporate each solution to approximately 2 mL on a

steam bath; then continue the evaporation to dryness under

infrared lamps on a hot plate

39.1.4 Remove the beakers from the hot plate, and dissolve

each residue in approximately 2 mL of H2SO4(1 + 35),

dis-pensed from a polyethylene wash bottle

39.1.5 Transfer each solution to a 12-mL centrifuge tubing

using three 2-mL rinses of H2SO4(1 + 35)

39.1.6 Add 5 drops of La(NO3)3·6 H2O (10 g/L) solution

and 0.1 mL of AgNO3solution (2.5 g/L) and approximately 1

g of (NH4)2S2O8to each centrifuge tube

39.1.7 Heat the tubes in a steam bath for 15 min

39.1.8 Remove the tubes from the steam bath, cool, and add

1 mL of HF (sp gr 1.15) Stir the mixture with a platinum

stirring rod; rinse the rod with HF (1 + 24) after each stirring After 5 min, centrifuge the tubes for 5 min

39.1.9 Withdraw the supernatant plutonium-containing so-lution by means of vacuum and transfer to a plutonium residue bottle Invert the tubes onto a tissue for 1 to 2 min; then draw off to the residue bottle any liquid that has drained down the inner wall of the tubes

39.1.10 Wash the precipitate by adding 3 mL of HF (1 + 24) and mixing with the platinum rod Rinse the platinum rod with

HF (1 + 24), wait 5 min, and centrifuge for 5 min Repeat the procedure in 39.1.9and proceed to step39.1.11

39.1.11 Add 1 mL of HClO4(70 to 72 %) to each tube and place the tubes in the heated aluminum heating apparatus for

30 min

39.1.12 Remove the tubes, cool, and add HClO4 (70 to

72 %) to adjust the volume in each tube to 0.5 mL

39.1.13 Transfer each solution to a 10-mL volumetric flask using the vacuum transfer device with three 2-mL water rinses; then add 0.5 mL of NH2OH·HCl solution to each flask 39.1.14 Prepare a reference solution by adding 0.5 mL of HClO4(70 to 72 %), 0.5 mL of NH2 OH·HCl solution (250 g/L), and 6 mL of water to a 10-mL volumetric flask 39.1.15 Place the flasks on a steam bath for 30 min 39.1.16 Remove the flasks from the steam bath, cool, and add 1 mL of Thorin solution to each flask Dilute to volume with water, stopper, and shake

39.1.17 Measure the absorbance of the solutions in 10-mm

cells versus the reference solution at a wavelength of 545 nm.

39.1.18 Process the data obtained in39.1.17in accordance with the procedure described in41.1

39.2 Checking Calibration Curve:

39.2.1 Each time a set of samples is analyzed verify the procedure and calibration factor by processing two 2-mL thorium standards and two blank solutions (with no thorium added) in accordance with the instructions in 39.1.2 through

39.1.17 39.2.2 Process the data obtained in 39.2.1 in accordance with the procedures described in39.2 If an individual calibra-tion value disagrees at the 0.05 significance level with the value of the constant obtained from the complete calibration set, investigate and rectify the cause of the difficulty before proceeding with further analyses

40 Procedure

40.1 Transfer a weighed aliquot of sample containing from

5 to 70 µg of thorium and no greater than 500 mg of plutonium into a 20-mL beaker and proceed with the analysis as described

in39.1.2through39.1.17 40.2 Calculate the thorium concentration in accordance with the procedure described in 41.3

41 Calculation

41.1 Equation for Calibration Data:

41.1.1 Calculate the corrected absorbance value for each standard calibration solution as follows:

where:

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Y = corrected absorbance value for the standard calibration

solution,

r = absorbance value obtained in 39.1.17 for the standard

calibration solution, and

s = average absorbance value obtained in 39.1.17 for the

duplicate calibration blanks

41.1.2 Use least squares formulas and the data from41.1.1

to calculate values of A and B in the linear calibration equation:

where:

A, B = constants (B should be approximately zero),

Y = corrected absorbance from41.1.1, and

x = micrograms thorium in the standard calibration

solu-tion

41.2 Individual Calibration Values:

41.2.1 Calculate the individual calibration value for each

standard solution processed with the samples as follows:

where:

A' = individual calibration value for each standard solution,

n = micrograms of thorium in standard solution,

m = corrected absorbance value for standard solution p − q

where:

p = absorbance value from standard solution, and

q = average absorbance of duplicate blank solutions from

39.1.17

41.2.2 Each individual A' should agree at the 0.05

signifi-cance level with the value of A obtained from the complete

calibration set

41.3 Determine the thorium concentration of the sample as

follows:

Th, µg/g Pu 5 R 5~Y 2 B!/AWC (10)

where:

A and B = constants in the linear calibration equation,

W = sample mass, g,

C = grams Pu per gram of sample, and

Y = a − b = corrected absorbance of sample solution

where:

a = absorbance value for sample solution, and

b = average absorbance value from the duplicate reagent

blanks described in39.2.1

42.1 The relative standard deviation is less than 2 % at

thorium concentrations between 66 and 144 µg/g Pu, 4 % at a

concentration of 34 µg/g Pu, and 11 % at a concentration of 10

µg/g Pu

42.2 The average value for thorium found in 91

measure-ments of 5 to 70 µg of thorium was 99 6 1 %

IRON BY 1,10-PHENANTHROLINE SPECTROPHOTOMETRIC TEST METHOD

43 Scope

43.1 This test method covers the determination of micro-gram quantities of iron in plutonium nitrate solutions

44.1 Ferric ion is reduced to ferrous ion with hydroxylamine hydrochloride Solutions of 1,10-phenanthroline and acetate buffer are added and the pH adjusted to 3.5 to 4.5 The absorbance of the red-orange complex [(C12H8N2)3Fe]+2 is read at 508 nm against a sample blank containing all of the

reagents except the 1,10-phenanthroline ( 6 ).

45.1 Plutonium must be reduced to Pu(III) to avoid causing interference

45.2 Silver and bismuth form precipitates

45.3 Tolerance limits for 2 µg/mL Fe for elements that

interfere in this determination are as follows ( 7 ):

46 Apparatus

46.1 Spectrophotometer, visible range with matched 10-mm

cells

47.1 Acetate Buffer Solution—Dissolve 410 g of sodium

acetate, (Na2C2H3O2) in water, add 287 mL of glacial acetic acid, and dilute to 1 L with water

47.2 Ammonium Hydroxide (1 + 9)—Dilute 1 volume of

NH4OH (sp gr 0.9) with 9 volumes of water

47.3 Hydrochloric Acid (1 + 9)—Dilute 1 volume of HCl

(sp gr 1.19) with 9 volumes of water

Dissolve 104 g of hydroxylamine hydrochloride (NH2OH·HCl)

in water and dilute to 1 L with water

47.5 Iron Standard (100 µg Fe/mL)—Carefully dissolve 100

mg of high-purity iron wire in 165 mL of HCl (1 + 1), cool, and dilute to 1 L with water

47.6 1,10-Phenanthroline Solution (0.2 weight/volume %)—

Dissolve 2 g of 1,10-phenanthroline in water and dilute to 1 L with water

48 Procedure

48.1 Transfer an aliquot of sample that contains 5 to 75 µg

of iron to a 30-mL beaker and add 10 mL acetate buffer

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solution and 1 mL of hydroxylamine hydrochloride solution.

Let solution stand for 10 min

48.2 Add 1 mL of 1,10-phenanthroline solution and adjust

the pH of the solution to the range from 3.5 to 4.5 with HCl

(1 + 9) or NH4OH

48.3 Transfer the solution to a 25-mL volumetric flask Use

water to wash the beaker and to dilute to volume Stopper the

flask and mix thoroughly

48.4 After 10 min, measure the absorbance of the sample

aliquot against a sample blank that contains all of the reagents,

except 1,10-phenanthroline, at a wavelength of 508 nm

N OTE 9—For sample aliquots that contain iron in the range of 5 µg, cells

of 5-cm length or longer should be used.

48.5 Prepare a calibration curve by adding to separate

30-mL beakers, containing 10 mL of acetate buffer solution and

1 mL of hydroxylamine hydrochloride solution, the following

amounts of iron standard: 0, 50, 100, 250, and 500 µL of iron

standard solution (100 µg Fe/mL) Follow the steps given in

48.2 through48.4 of the procedure; then plot the absorbance

versus the micrograms of iron per 25 mL final volume of the

solution

49 Calculation

49.1 Calculate the iron in micrograms per gram of

pluto-nium as follows:

Fe, µg/g Pu 5 C/PW (11)

where:

C = micrograms of Fe from calibration curve,

W = weight of sample, g, and

P = Pu, g/g of sample

50.1 The relative standard deviation is 6 %

IMPURITIES BY ICP-AES

(Cationic impurities may be determined using Test Method

C1432(Impurities by ICP-AES) with appropriate sample

preparation and instrumentation

CHLORIDE BY THIOCYANATE

SPECTROPHOTOMETRIC TEST METHOD

51 Scope

51.1 This test method ( 8 ) is used to determine chloride in

plutonium nitrate solution

52.1 After the sample aliquot is mixed with a solution

containing ferrous ammonium sulfate, sulfamic acid,

phos-phoric acid, and sulfuric acid, the chloride is steam distilled at

a temperature of 140°C (Note 10) An aliquot of the distillate

is mixed with ferric ammonium sulfate and mercuric

thiocya-nate solutions Thiocyathiocya-nate ion is released in direct proportion

to the chloride ion concentration The absorbance of the

resulting red-brown ferric thiocyanate complex is read at 460

nm against a reagent blank

N OTE 10—Save a portion of the distillate to use for the fluoride determination.

53.1 Iodide, bromide, cyanide, and thiocyanate ions inter-fere Nitrite interference is eliminated by use of sulfamic acid

54 Apparatus

54.1 Steam Distillation Apparatus, including a steam

gen-erator and heating mantles

54.2 Spectrophotometer and Matched 10-mm Cells.

55.1 Chloride Standard Solution (5 µg Cl/mL)—Prepare a

stock solution, A, Cl = 500 µg/mL, by dissolving 824.4 mg of dried NaCl in water and diluting to 1 L Prepare chloride standard, 5 µg Cl/mL, by diluting 10 mL of stock solution A to

1 L with water

55.2 Ferric Ammonium Sulfate Solution (0.25 M)—

Dissolve 12 g FeNH4(SO4)2·12 H2O in H2SO4 (5 + 95) and dilute to 100 mL with H2SO4(5 + 95)

55.3 Ferrous Ammonium Sulfate (0.2 M) Sulfamic Acid (0.5 M) Solution—Dissolve 78.4 g of Fe(NH4)2(SO4)2·6 H2O and 48.6 g of NH2SO3H in H2SO4(5 + 95) and dilute to 1 L with

H2SO4(5 + 95)

55.4 Mercuric Thiocyanate Solution (saturated)—Add

Hg-(SCN)2to 90 % ethyl alcohol until the solution is saturated

56 Procedure

56.1 Transfer 25 mL of acid mixture consisting of 0.2 M ferrous ammonium sulfate-0.5 M sulfamic acid solution,

phos-phoric acid, and sulfuric acid mixed in the ratio 1 + 1 + 2.5, to

a steam distillation flask and steam distill at 140°C until 100

mL of distillate is collected Retain this solution for use as a reagent blank

56.2 Transfer an accurately weighed aliquot of plutonium nitrate solution that contains approximately 500 mg of pluto-nium to a steam distillation flask and add 25 mL of acid mixture as described in56.1 Steam distill at 140°C until 100

mL of distillate is collected

56.3 Transfer up to 6 mL of sample distillate, and 6 mL of reagent blank distillate, to separate 10-mL volumetric flasks

To each flask, add 2 mL of 0.25 M ferric ammonium sulfate

solution, 2 mL of saturated mercuric thiocyanate solution, and dilute to volume with water solution and mix

56.4 After 10 min, transfer the solutions to 1-cm cells and

measure the absorbance of the sample versus the reagent blank

at a wavelength of 460 nm

56.5 Prepare a calibration curve by adding 0, 0.5, 1, 2.5, and

4 mL of the chloride standard (5 µg Cl/mL) to 10-mL volumetric flasks and dilute to about 5 mL with water solution

Add 2 mL of 0.25 M ferric ammonium sulfate solution and 2

mL of mercuric thiocyanate solution, mix, and dilute to volume with water solution Mix solutions again and after 10 min transfer the solution to 1-cm absorption cells and read the

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absorbance versus a reagent blank at a wavelength of 460 nm.

Plot the micrograms of Cl per 10 mL of solution versus the

absorbance reading

57 Calculation

57.1 Calculate the micrograms of Cl per gram of plutonium

as follows:

Cl, µg/g Pu 5 CD/WP (12)

where:

C = micrograms Cl from calibration curve,

D = dilution factor = distillate, mL/aliquot of distillate,

mL,

W = weight of sample, g, and

58.1 The precision and bias of this test method is 1006 5 %

with a sodium chloride matrix No plutonium standard is

available

FLUORIDE BY

DISTILLATION-SPECTROPHOTOMETRIC TEST METHOD

59 Scope

59.1 This test method covers the determination of

micro-quantities of fluoride in plutonium nitrate solutions

60.1 Fluoride is separated from the plutonium nitrate

dis-solved in a mixture of phosphoric and sulfuric acid by steam

distillation at 140 6 5°C (Note 11) The fluoride, in an aliquot

of the distillate, is complexed with Amadac F and the

absor-bance of the blue-colored complex is read in 1-cm cells versus

a reagent blank at a wavelength of 620 nm

N OTE 11—An aliquot of the distillate from the test method for the

determination of chloride (see 52.1 ) can also be used to determine

fluoride.

61.1 Sulfate or phosphate ions, which may be carried over

by bumping or steam distillation at too high a temperature,

cause low absorbance reading by bleaching the colored

com-plex The formation of the colored complex is sensitive to pH

range and high salt concentration

62 Apparatus

62.1 See Section54

63.1 Amadac F Solution (0.1 g/mL)—Dissolve 10 g of

Amadac F reagent in 60 % isopropyl alcohol in a 100-mL

volumetric flask and dilute to volume with 60 % isopropyl

alcohol

63.2 Fluoride Standard Solution (10 µg F/mL)—Prepare a

stock solution, 1.000 mg F/mL, by dissolving 2.210 g of dry

NaF in water and diluting to 1 L Pipet 10 mL of stock solution,

1.000 mg F/mL, into a 1-L volumetric flask and dilute to volume with water to prepare the fluoride standard, 10 µg F/mL

64 Procedure

64.1 Transfer 20-mL aliquots of the sample and of the reagent blank distillates, which were prepared during the determination of chloride, to 50-mL beakers and adjust the pH

to 5.0 to 5.2 by the addition of fluoride-free NaOH solution or HCl Dilute these solutions to 25 mL

64.2 Transfer 8-mL aliquots of the solutions prepared in

64.1to 10-mL flasks and add 2 mL of Amadac F reagent (0.1 g/L) to each solution and mix

64.3 Allow the solutions to stand 1 h; then measure the

absorbance of the blue-colored complex in the sample versus

the reagent blank solution at a wavelength of 620 nm in 1-cm cells

64.4 To prepare a calibration curve, pipet 0, 50, 100, 200,

500, and 1000-µL aliquots of the fluoride standard solution (10

µg F/mL) into separate 10-mL volumetric flasks Add 2 mL of Amadac F solution (0.1 g/L) to each flask and dilute to volume Mix, allow solutions to stand in the dark for 1 h, and measure

the absorbance of each in 1-cm cells versus a reagent blank at

a wavelength of 620 nm Plot the micrograms of fluoride in the

10-mL volume of solution versus the absorbance.

65 Calculation

65.1 Calculate the fluoride in micrograms per gram of plutonium as follows:

F, µg/g Pu 5 CD/WP (13)

where:

C = micrograms of F from calibration curve,

D = dilution factor = V1V2/A1A2 where:

V1 = volume of distillate,

A1 = aliquot from V1, mL,

V2 = volume to which A1is diluted, mL, and

A2 = aliquot of V2taken for analysis, mL,

W = weight or original sample aliquot, g, and

66.1 Precision and bias of the analysis is 100 6 5 % with a sodium fluoride matrix No plutonium matrix standard is available

SULFATE BY BARIUM SULFATE TURBIDIMETRIC

TEST METHOD

67 Scope

67.1 This test procedure covers the determination of the sulfate concentration in plutonium nitrate solutions in the range from 50 to 700 µg/g of plutonium

68.1 In plutonium nitrate solutions plutonium is removed by extraction with tributylphosphate, TBP The sulfate in the

Tiêu đề	Standard Test Methods for Chemical, Mass Spectrometric, Spectrochemical, Nuclear, and Radiochemical Analysis of Nuclear-Grade Plutonium Nitrate Solutions
Thể loại	tiêu chuẩn
Năm xuất bản	2010

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